1. Field of the Invention
The present invention relates to a hand-held image capture apparatus, and to a method of using such apparatus.
2. Description of the Related Art
Hand-held swipe scanners for capturing an image are well-known. Such a scanner typically has a linear array of photodetectors arranged behind an imaging system such as an elongate moulded plastic focussing element. The focussing element is swiped in contact or near-contact across an object to be imaged, for example a document, in a direction transverse to the linear photodetector array. Means are provided to detect the linear distance travelled by the scanner so that an image can be built up from data captured from the array as the scanner is swiped over the object being imaged. Usually, the scanner device has means by which images captured from laterally adjacent swipes can be stitched together. An example of such a scanner is described in patent document WO 96/27257.
The swipe scanner may have an in-built optical source to illuminate the object to be scanned in the region imaged by the detector array, for example a linear stripe of near infrared or visible radiation.
Conventional swipe scanners are able to scan documents at a speed of up to about 300 mm/s in the direction transverse to the detector array.
Most swipe scanners capture images not in colour but with a grey-scale. Although it may in principle be possible to devise a swipe scanner that would capture colours as well as a grey scale, there are a number of technical problems, such as the need to illuminate the object with white light, and to have additional detector elements for detecting different colours. This adds to the cost and complexity of the swipe scanner, particularly if it is desired to maintain a swipe capture speed comparable with grey-scale swipe scanners. As a result, most commercially available swipe scanners capture images only in grey-scale even though there is an increasing need for colour capture of images. Swipe scanners that do capture images in colour are expensive and have to be tethered to a portable personal computer for power and data transfer.
Another limitation of conventional swipe scanners is the relative difficulty of keeping track of what has been scanned. A particular image may be given a file name, but this may not be sufficiently memorable or convey sufficient information regarding the scanned image. Although it is in principle possible to incorporate other information entry means, such as a keyboard, with a hand-held scanner, this may be inconvenient owing to the lack of physical space on the device. A user of the device may also find it less than convenient to spend significant time entering such information, particularly when the time taken to swipe an image is small by comparison.